Pneumatic controls for high-voltage air blast circuit breakers



Jan. 15, 1963 3,073,932

R. SCHUL PNEUMATIC CONTROLS FOR HIGH-VOLTAGE AIR BLAST CIRCUIT BREAKERSFiled Sept. 25, 1959 3 Sheets-Sheet 1 f I i Jan 15, 1963 R. SCHULZ3,073,932

RNEUMATIO CONTROLS FOR HIGH-VOLTAGE AIR BLAST CIRCUIT BREAKERS 5Sheets-Sheet 2 Filed Sept. 25, 1959 y MMT-@AMW Jan. 15, 1963 R. SCHULZ3,073,932

PNEUMATTO CONTROLS FOR HIGH-VOLTAGE ATR BLAST CIRCUIT BREAKERS FiledSept. 25, 1959 3 Shees-ShaelI 3 3 @735 932 annemarie contre-lors nonmon-vorraus. All?. BLAST QERCUHT BREAKERS Richard Schulz, Friedberg,Hesse, Germany, assigner to Voigt 8: Haerner a., Frankfurt am Main,Germany snes sept. ze, 1959,. er. No. astma Ciaims priority, applicationGermany Sept. 24, 19% 1l Claims. (Qi. 2Go- 143) rlhis invention hasreference to high-voltage circuit breakers, and more particularly topneumatically operated high-voltage air bla-st circuit breakers.

It is a general object of this invention to improve the control of suchcircuit breakers.

Circuit breakers of the aforementioned character may be designed forcircuit voltages of say 220 kv., and generally comprise a hollowinsulating column which supports adjacent to its upper end pairs ofcooperating separable contacts, fluid motor means for operating thesecontacts and means for producing arc-extinguishing blasts of gas acrossthe gaps formed between the contacts upon separation thereof.

In circuit breakers of the aforementioned character it is desirable toprovide a supply of air under pressure adjacent the top end of thehollow insulating column from which air under pressure may be derived tocontrol the operation of the movable parts of the circuit breaker, tooperate its contact-operating fluid motors and blast valves and toestablish the arc-extinguishing air blasts. This location of the supplyof air under pressure for control purposes makes it possible to minimizecircuit breaker times because it minimizes the distance between thevalves which admit air under pressure to the pneumatic control system ofthe circuit breaker and which vent said control system to atmosphere.Since the top of the hollow insulating column is at an elevatedpotential, such a supply of air under pressure is also at an elevatedpotential, and so are the valve means for admitting air under pressurefrom the supply to the pneumatic control system of the circuit breakerand for venting the latter. In the interest of speed of operation suchvalves must be operated by positive means having a minimum of inertia orweight.

it is a special object of this invention to provide improved controlmeans for high voltage circuit breakers of the aforementioned character,and more particularly improved valve means at an elevated potentialsituated adjacent the top of the hollow insulating column for admittingair under pressure to the control system of the circuit breaker and forventing its control system to atmosphere.

It is another object of this invention to provide valve means at theaforementioned location for the aforementioned purpose which valve meansdene a substantially straight path for the flow of air under pressurewhich is controlled by the valve means.

It is still another object or this invention to provide valve means atthe aforementioned location for the aforementioned purpose which valvemeans require but small forces for their operation and, therefore, lendthemselves to be operated by linkages whose mechanical strength andweight is relatively small, and which can, therefore, readily be movedat relatively high initial speeds.

Mechanical means which are mainly subjected to tensile stresses ratherthan compression lend themselves to combinihg the requirements ofrelatively high mechanical strength and relatively small weight. Itis,therefore, another object of the invention to provide valve means at theaforementioned location and for the aforementioned purpose adapted to beoperated by mechanical means which are mainly subjected to tensilestresses.

Another object of the invention is to provide valve Patented dan. l5,i953 means at the aforementioned location for the aforementioned purposewhich are coupled in such a way with an operating or push and pull rodas to preclude changes in ambient temperature resulting in changes inthe length'of the rod to affect the valve means and the operationthereof.

For a better understanding of the invention reference may be had to theaccompanying drawings in which:

FIG. l is a section along 2 2 of FlG. 2 and shows diagrammatically someof the parts of a high-voltage circuit breaker which are at an elevatedpotential and supported by, and arranged adjacent the top end of ahollow insulating col-umn;

FIG. 2 is a top plan View of the structure shown in FIG. l;

FIG. 3 'shows the whole insulating column and some of the partsassociated with it partly in side elevation and partly in verticalsection; and

FlG. 4 is a vertical section on a larger scale than FG. 3 ot" the topend of the insulating column and the parts contained therein orassociated with it.

The structure shown in FIGS. l and 2 is substantially prior art, and theinvention proper has been illustrated in FIGS. 3 and 4.

Referring now to FIGS. l and 2, the two circuit `breaker heads 6, 7 aresupported by a hollow insulating column 1 fully shown in FIG. 3. Bothcircuit breaker heads or casings 6, '7 are made of metal, and are at anelevated potential. Studs 2c in bushings 2a are used for seriallyconnecting the separable cooperating contacts in casings 6, 7 tocontacts situated in adjacent casings of the same kind, as more fullyshown in my copending patent application Ser. No. 610,868, tiledSeptember 19, 1956 for Fluid Pressure Operated Circuit Breaker PoleUnits, now U.S. Patent 2,964,605 issued December 13, 1960. Referencenumeral 4 has been applied to generally indicate a control mechanismarranged adjacent the upper end of column l. The control mechanism 4 hasbeen shown on larger scales in FIGS. 3 and 4. The inside of column 1accommodates a rod 8 of insulating material adapted to operate thecontrol mechanism 4 from the lower end of column l which is at groundpotential. Air under pressure is admitted from a tank 2 situated at thebottom end of col-umn i (see FG. 3) into column 1 and is furtheradmitted from the upper end of column l into circuit breaker heads orarcing chambers d, 7 wherein xed plug contacts 16 and cooperating nozzlecontacts t7 are accommodated. The right end or" .nozzle contact .1.7, asseen in FlG. l, forms a piston l and is acted upon by a closing spring19. Blast valve 2@ adapted to open venting port 23 is operated by afluid motor, or pneumatic motor, which includes piston 21. The latter isbiased by spring 22 and may be operated by air under pressure admittedthrough control pipe line 24 forming part of a pneumatic control system.

In the position of the parts shown in FG. l the arcing chambers 6, 7housing contacts 16, 17 are lled with air under pressure admitted tothem from the upper end of hollow supporting insulator 1. There is noair under pressure in pipe line 24, and hence blast valve Zi) is in theclosed position shown. When air under pressure is admitted to pipe line24, piston 21 moves from right to left against the bias of spring 22 andin so moving opens blast valve 2). As a result, the pressure inside ofthe arcing chambers d, '7 accommodating contacts 16 and t7 movescontacts 17 and pistons 18 from their closed position shown in FIG. 1 tothe open position thereof. This movement is effected against the bias ofspring i9. The arcs formed between contacts 16 and 17 are quicklyextinguished by the blast of air venting through port 23. While thearc-extinguishing blast still lasts, a disconnect (not shown) may beopened, providing a permanent break in the interrupted circuit. Blastvalves 20 close 3 when the pressure in pipe lines 24 is allowed torecede, as by venting thereof. As a result, springs 19 causere-engagement of contacts 16 and 17.

This invention is concerned with valve means for venting the pneumatic'system formed by pipe lines 24 and for admitting air under pressure intothat pneumatic system.

. Referring now t'o FIGS. 3 and 4, the upper end of column 1 supports acasing 3 of metal which forms a supply of air under pressure. Supportingcolumn 1 is lmounted on a tank 2 containing air under pressure, and airunder pressure contained in tank 2 may iiow through column 1 into casing3 on the top of column l. Tank 2 is at ground potential,v whereas metalcasing 3 is at an elevated potential. Both circuit breaker heads 6 and7` and the pneumatic control system 24 may be supplied with air underpressure derived from casing 3. The valve means I4 adjacent the upperend of column 1, i.e. inside of casing 3, control the flow of air underpressure from casing 3 into control system 24. Valve means 4 are alsoadapted to vent control system 24 to atmosphere. Valve means 4 includemeans defining a substantially straight passageway 9 having anupstreamend 9 and a downstream end 9". Valve element 10 is arrangedadjacent the upstream end `9 of passageway 9 and adapted to cooperatewith a valve seat coextensive with the upstream end 9 of passageway 9.Valve element 10 has two limit positions, namely a closed positionwherein it engages the valve seat, and an open position wherein it ismoved downwardly, or in upstream direction, into casing 3. Valve means 4further include a second valve element 12 arranged adjacent thedownstream end 9" of passageway 9 and adapted to control the ventingorifices 13 provided in a casting mounted on casing 3 and definingpassageway 9 as well as venting orifices 13'. Another casting mounted onthe aforementioned casting defines an orifice S for admitting air underpressure from casing or housing 3 to conduits 24. The valve element 12has a seal-off position wherein it closes the venting orifices 13, and aventing position wherein it opens the orifices 13. Valve elements 10 and12 are mounted on a common stem 14. When valve element r10 is in theopen position thereof valve element 12 is in the seal-olf positionthereof. When valve element 10 is in its closed position valve element12 is in the venting position thereof. Valve element 12 has an upstreamsurface cooperating with the orifices 13 tov close the same and adownstream surface. A duct 11 extends transversely to said upstreamsurface and said downstream surface. This duct allows air under pressureto iiow from the supply of air under pressure formed by easing 3 tocontrol system 24 when valve element 12 is in the seal-off positionthereof. In FIG. 4 the flow of air under pressure through duct 11 hasbeen indicated by a pair of arrows extending in the direction of theflow of air through duct 11 formed by valve element 12. Stem 14 isguided in a fixed frame structure 16. One end of helical stem-biasingspring 15' rests against the valve element 10, while the opposite end ofspring l15' rests against the aforementioned fixed frame structure 16.It

will be thus apparent that spring 15 biases valve element 60 10 to theclosed position thereof, and biases valve element 12 to the ventingposition thereof. Both valve elements 10 and 12 are arranged in coaxialrelation. The insulating rod S inside column 1 is in coaxial relation tocolumn 1, to valve elements 10 and 12 and to stem 65 vertical armsupporting roller means 26. Reference numeral 19 has been applied toindicate the point of cooperative engagement of levers 1'7, 18 and stem14. The upper end of rod 8 supports a cam 23 engaged by roller means 2oand controlling the movement of levers 17', 1S. Cam 23 comprises a firstpair of oblique surfaces 22' converging in upward direction, a secondpair of oblique surfaces 22 converging in downward direction, and athird pair of vertical surfaces parallel to the aforementioned planeextending vertically through rod 8. The third pair of surfaces of cam23' is arranged intermediate the first pair of surfaces 22 and thesecond pair of surfaces 22". No reference numeral has been applied tothe third pair of surfaces of cam 23. As shown in FIG. 4, `the thirdpair of surfaces of cam 23 is engaged by roller means 26. A pair ofbolts or studs 24' and 25' is secured to the upper end of rod 8, i.e. tocam'23'. Bolts or studs 24, 25' are adapted to slidably engage coaxialbores 24, 25 defined by fixed frame structure 16.

When roller means 26 engage the'lower converging sur `faces 22 of cam 23and rod 8 is pulled indownward direction, the spacing between rollerlmeans 26 is progressively increased,` resulting in a pivotal movementof levers 17 and 18 and concomitant lowering of point 19" where levers17' and 18 are operatively secured to stem'` 14. C0nsequently stem 14'islowered, and spring 15I compressed, when rod 8 is pulled in downwarddirection..

In other words, the force needed for compressing spring:

15 stresses rod 8 which has in inherently high tensile strength. Valveelement 10 is in its fully open position and valve element 12 is in itsfull seal-olf position when rollers 26 move from. the lower slantingsurfaces 22 of cam 23 to its parallel vertical surfaces. On upwardmovement of rod 8 rollers 26 are caused t-o engage again the twosurfaces 22 on cam 23' which converge in downward direction. As aresult, spring 15 is allowed to expand, moving valve element 10 towardits higher or closed position, and moving valve element 12 toward itshigher or venting position. When rod 8 is pushed'upwardly it is placedunder compression, but the forces of compression are minimal since theentire valve means 4 is then operated by the energy stored in spring 15,and rod S is merely subjected to the small frictional forces of the cam'and lever mechanism 23', 17", 18'. The upper end of rod 8 is guidedalong a straight path by means of the cooperatin-gA guiding means 24',24 and 25", 2S". When stern 14 is in its lower position shown in FIG. 4,the pressure of air against the downstream surface of valve element 12tends to maintain both valve elements 12 and 10 in the lower positionthereof. When stem 14 has been moved -to the upper position thereof, thepressure of air against the upstream surface of valve element 1u tendsto maintain both valve elements 10 and 12 in the higher positionthereof. Thus no forces have to be transmitted through rod 8' uponhaving moved valve assembly 4 to one of the two limit positions thereof.Since rod 3 is mainly subjected to tensile stress, and has an inherentlyhigh tensile strength, its weight may be light and its speed ofoperation high.

The path of compressed air from the supply 3 through passage 9 and theorifice 5 by which the upper end of valve assembly 4 is connected to thecontrol system 24- is substantially a straight line. This tends toestablish a rapid fiow of air toward and in control system 24, and'consequently a rapid operation 0f the blast valve and a rapid separationof the cooperating contacts of the circuit breaker.

It will also be apparent that slight changes in the length of rod 8 ascaused by changes intemperature have no effect whatever on t-heVoperation ofl valve mechanism 4.

lt will be understood that although but one embodiment of the inventionhas been illustrated and described in detail, the invention is notlimited thereto. It will also be understood that the .structureillustrated may be modied without departing from the spirit and scope ofthe invention as set forth in the accompanying claims.

l claim as my invention:

l. in a high-voltage circuit breaker the combination of a verticalhollow insulating column; relatively movable contact means arrangedadjacent the upper end of said column; a blast valve arranged adjacentthe upper end of said column for producing an arc-extinguishing blastacross the gap formed between said Contact means upon separationthereof; means for filling said column with air under pressure; apneumatic system for said contact means and blast valve arrangedadjacent the upper end of said column and including tluid motor meansfor operating said contact means and said blast valve; said pneumaticsystem further comprising valve means for selectively admitting airunder pressure to said fluid motor means and for venting said fluidmotor means to atmosphere; said valve means including a valve housingaligned with said column, supported by the upper end thereof andpermanently communicating with said upper end, said valve housingdefining a substantially straight passageway in coaxial relation to saidcolumn; a first valve element arranged Iadjacent the upstream end ofsaid passageway and having a first limit position causing opening ofsaid passageway and a second limit position causing closing of saidpassageway; a second valve element arranged in coaxial relation to saidrst valve element adjacent the downstream end of said passageway andhaving a iirst limit position causing said passageway to be sealed odfrom atmosphere and a second limit position causing said passageway tobe vented to atmosphere; a common stem supporting said first valveelement and said second valve element to move said first valve elementand said second valve element jointly to said first limit positions andsaid second limit positions thereof; spring means biasing said firstvalve element and said second valve element to said second limitpositions thereof; said second valve element defining a duct extendingin a direction substantially longitudinally of said stem causing thepressure or" air passing said first valve element and said duct tomaintain said second valve element and said first valve element in saidsecond limit positions thereof; and an insulating rod arranged insidesaid column adapted to be moved in directions longitudinally thereof andoperatively related to said stern to operate said valve means from thebottom end of said column.

2. ln a high-voltage circuit breaker the combination of a verticalhollow insulating column; relatively movable contact means arrangedadiacent the upper end of said column; a blast valve arranged adjacentthe upper end of said column for producing an arc-extinguishing blastacross the gap formed between said Contact means upon separationthereof; a taule at the lower end of said column for filling said columnwith gas under pressure; a pneumatic system for said `Contact means andblast valve arranged adjacent the upper end of said column and includingfluid motor means for operating said contact means and said blast valve;said pneumatic system further comprising valve means for selectivelyadmitting gas under pressure to said fluid motor means and for ventingsaid fluid motor means; said valve means includa valve housing alignedwith said column, supported by the upper end thereof and permanentlycommunicating with said upper end, said valve housing defining asubstantially straight passageway for gas under pressure; a valve seatformed by the intake end of said passagewaydelining means; a first valveelement movable in a direction longitudinally of said passageway betweenlimit positions situated at points upstream of said intake end toselectively engage said valve seat and be disengaged from said valveseat; orifice means for venting said passageway and said fluid motormeans; a second valve element arranged in coaxial relation to said firstvalve element at a point of said passageway situated downstream of saidfirst valve element; said second valve element comprising a downstreamsurface and an upstream surface adapted to selectively close saidorifice means and open said orifice means; a common stem supporting saidfirst valve element and said second valve element; a helical springsurrounding said stern and biasing said first valve element intoengagement with said valve seat and biasing said second valve element tothe orifice means opening position thereof; said second valve elementdefininfr a duct extending in a direction substantially longitudinallyof said stern to cause gas under pressure passing through said duct topress against said downstream surface of said second valve element tomaintain said second valve element in said orifice closing positionthereof and to maintain said rfirst valve element out of engagement withsaid valve seat thereof; and an insulating rod arranged inside saidcolumn adapted to be moved in directions longitudinally thereof andoperatively related to said stem to operate said valve means from thebottom end of said column.

3. ln a high-voltage circuit breaker the combination of a verticalinsulating column; relatively movable contact means arranged adjacentthe upper end of said column; a blast valve arranged adjacent the upperend of said column for producing an arc-extinguishing blast across thegap formed between said contact means upon separation thereof; means forfilling said column with gas under pressure; a pneumatic system for saidcontact means and blast valve arranged adjacent the upper end of saidcolumn and including fluid motor means for operating said Contact meansand said blast valve; said pneumatic system further comprising valvemeans for selectively admitting under pressure to said `fluid motormeans and for venting said fluid motor means to atmosphere; said valvemeans including a valve housing aligned with said column, supported bythe upper end thereof and permanently communicating with said upper end,said valve housing defining a substantially straight passageway for gasunder pressure; a first valve element arranged tadjacent the upstreamend of said passageway and having a first limit position causing openingof said passageway and a second limit position causing closing of saidpassageway; a second valve element arranged in coaxial relation to saidfirst valve element adjacent the downstream end of said passageway andhaving a rst limit position causing said passageway :and said liuidmotor means to be sealed-off from atmosphere and a second limit positoncausing venting of said passageway and of said fluid motor means toatmosphere, said second valve element having an upstream surface and adownstream surface and defining a duct extending substantiallytransersely across said upstream surface and said downstream surface tocause gas under pressure passing through said duct to press against saiddownstream surfact to maintain said second valve element in said secondlimit positions thereof; a common stem supporting said iirst valveelement and said second valve element to cause said first valve elementto assume said first limit position thereof when said second valveelement is in said first limit position thereof; spring means biasingsaid stem to move said first valve element and said second valve elementto said second limit positions thereof; an insulating rod arrangedinside said column extending in a direction longitudinally of saidcolumn for operating said stern from the bottom end of said column; acam arranged inside said valve housing and supported on the upper end ofsaid rod; and a pair of pivotally mounted bell-cranlr-shaped levers alsoarranged inside said valve housing each having one arm in cooperativeengagement with said stem land each having another arm under the controlof said cam.

4. An arrangement as specified in claim 3 wherein each of said pair oflevers is provided witi one of a pair of rollers in engagement with saidcani, and wherein envases said cam has a pair of converging surfaces anda pair of parallel surfaces.

5. In a high-voltage circuit breaker the combination of a verticalhollow insulating column; relatively movable contact means arrangedladjacent the upper end of said column for producing anarc-extinguishing blast across the gap formed between said contact meansupon separation thereof; a tank at the lower end of said column forfilling said column with gas under pressure; a pneumatic system for saidcontact means and blast valve arranged adjacent theI upper end of saidcolumn and including duid motor means for operating said contact meansand said blast valve; said pneumatic system further comprising valvemeans for selectively admitting gas under pressure to said fluid motormeans and for venting said fluid motor means to atmosphere; said valvemeans comprising a valve housing aligned with said column, supported bythe upper end thereof and permanently communicating `with said upperend, said valve housing deiining a substantially straight passageway forgas under pressure; a tirst valve element arranged adjacent the upstreamend of said passageway and having a iirst limit position causing openingof said passageway and a second limit position causing closing of saidpassageway; a second valve element arranged in coaxial relation to said:lirst valve element adjacent the downstream end of said passageway andhaving a rst limit position causing said passageway and said fluid motormeans to be sealed-off from atmosphere and a second limit positioncausing said iluid motor means to be vented to atmosphere, said secondvalve element having an upstream surfface and a downstream surface anddefining a duct extending substantially transversely across saidupstream surface and said downstream surface to cause gas under pressurepassing through said duct to act against said downstream surface therebymaintaining said second valve element in said -rst limit positionthereof; a common stern supporting said rst valve element and saidsecond valve element to cause joint movement of said first valve elementand of said second valve element to said -iirst limit positions thereofand joint movement of said tirst valve element and of said second valveto said second limit positions thereof; spring means resting againstsaid valve housing biasing said iirst valve element and said secondvalve element to said second limit positions thereof; an insulating rodarranged inside said column for operating said stem arranged in coaxialrelation to said stem; a substantially wedge-shaped cam arranged insidesaid valve housing on the upper end of said rod; a pair ofbell-crank-shaped levers also arranged inside said valve housingpivotally mounted on said valve housing each having one arm incooperative engagement with said stem and each having another arm underthe immediate control of said cam, and cooperating guide means on saidvalve housing and on said cam for guiding the upper end of said rod inVa direction longitudinally thereof.

6. In a high-voltage circuit breaker the combination of a verticalhollow insulating column; relatively movable contact means arrangedadjacent the upper end of said column for producing an arc-extengiushingblast across the gap formed between said contact means upon separationthereof; a pneumatic system for said contact means and said blast valvearranged adjacent the upper end of said column and including fluid motormeans for operating said contact means and said blast valve; a supply ofair under pressure lfor filling said column with iair under pressure;valve means adjacent the upper end of said column for admitting airunder pressure from said column to said tluid motor means and forventing said fluid motor means to atmosphere, said valve means having avalve housing aligned with said column, supported by the upper endthereof and permanently communicating with said upper end, said Valvehousing accommodating a pair of valve elements having a pair of limitpositions; a compression spring biasing said valve elements to one ofsaid pair of limit positions; an insulating rod arranged inside saidcolumn extending in a direction longitudinally of said solumn foroperating said vaive elements from the lower end of said column; and acoupling connecting said valve elements to said rod adapted to cause aldownward pull on said rod to compress said spring and move said valveele-ments to one of said pair of limit positions and to cause an upwardpush on said rod to release said spring and allow said valve elements tobe moved by said spring to the other of said pair of limit positions.

7. In a high-voltage circuit breaker the combination of a verticalhollow insulating column; relatively movable contact means arrangedadjacent the upper end of said column; a blast valve arranged adjacentthe upper end of said column for producing an arc-extinguishing blastacross the gap formed between said contact means upon separationthereof; a pneumatic control system for said contact means and saidblast valves arranged adjacent the upper end of said column andincluding fluid motor means for operating said contact means and saidblast valve; a supply of air under pressure for filling said column withair under pressure; valve means adjacent the upper end of said columnfor admitting air under pressure from said column to said fluid motormeans and for venting said uid motor means to atmosphere; said valvemeans including a valve housing aligned with said column, supported bythe upper end thereof and permanently communicating with said upper end,said valve housing defining a passageway connecting said fluid motormeans with said upper end of said column; said valve Vmeans furtherincluding a first valve element arranged `adjacent the upstream end ofsaid passageway and having an open position and a closed position; saidvalve means further including a second valve element arranged adjacentthe downstream end of said passageway having a seal-off position and aventing position and defining a duct allowing air under pressure to flowfrom said upper end o'f said column to said liuid motor means when saidsecond valve element is in said seal-ofi position thereof; a stemconnecting said first valve element and said second valve element tocause joint movement of said first valve element to said open positionthereof and of said second valve element to said seal-ott positionthereof; spring means biasing said iirst valve element to said closedposition thereof and biasing said second valve element to said ventingposition thereof; and insulating rod arranged inside of said columnextending in a direction longitudinally thereof for operating said stemfrom the lower end of said column; pivotally mounted bell-crank-shapedlever means arranged inside said valve housing having one arm inoperative engagement with said stem and another `arm adapted to beoperated by said rod; and cam means also arranged inside said valvehousing on the upper end of said rod in operative engagement with saidother arm, said cam means comprising a first surface adapted to causesaid lever means to be pivoted in one direction against the bias of saidspring means by downward pull of said rod; and said cam means furthercomprising a second surface adapted to allow said lever means to bepivoted in the opposite direction under the action of said spring meansupon an upward push of said rod.

8. In a high-voltage circuit breaker the combination of a verticalhollow insulating column; relatively movable contact means arrangedadjacent the upper end of said column; a blast valve arranged adjacentthe upper end of said column for producing an arc-extinguishing blastacross the gap formed between said contact means upon separationthereof; a pneumatic system for said contact means and blast valvearranged adjacent the upper end of said column and including iiuid motormeans for operating said contact means and said blast valve; a supply ofair under pressure for filling said column with air under pressure;valve means adjacent the upper end of said column for admitting airunder pressure from said column to said fiuid motor means `and forventing said uid motor means to atmosphere; said valve means including avalve housing aligned with said column, supported by the upper endthereof and permanently communicating with said upper end, said valvehousing defining a passageway connecting said upper end of said columnto said liuid motor means; said valve means further including a firstvalve element arranged adjacent the upstream end of said passageway andhaving an open position and a closed position; said valve means furtherincluding a second valve element arranged adjacent the downstream end ofsaid passageway having a seal-off position and a venting position anddefining a duct allowing air under pressure to fiow from said upper endof said column to said fluid motor when said second valve element is insaid seal-od position thereof; a stem connecting said first valveelement and said second valve element to cause joint movement of saidfirst valve element to said open position thereof `and of said secondvalve element to said seal-off position thereof; a helical compressionspring surrounding said stem biasing said first valve element to saidclosed position thereof and biasing said second valve element to saidventing position thereof; a vertical insulating rod arranged inside saidcolumn for operating said stem from the lower end of said column; a pairof pivotally mounted bell-crank shaped levers accommodated inside saidvalve housing arranged symmetrically in regard to a plaie extendingvertically through said rod, each of said pair of levers having asubstantially horizontal arm in operative engagement with said stem anda substantially vertical arm supporting a roller means; and cam meansalso arranged inside said Valve housing on the upper end of said rod inoperative engagement with said substantially vertical arm of said pairof levers, said cam means comprising a first pair of oblique surfacesconverging in downward direction, and a second pair of vertical surfacesparallel to said plane extending vertically through said rod.

9. In a high-voltage circuit breaker the combination of a verticalhollow insulating column; a pneumatic system adjacent the upper end ofsaid column and including fluid motor means for operating said contactmeans and said blast valve; a supply of air under pressure for fillingsaid column with air under pressure; Valve means adjacent the upper endo t said column for admitting of air under pressure from said column tosaid fluid motor means and for venting said fiuid motor lmeans toatmosphere; said valve means including a valve housing aligned with saidcolumn, supported by the upper end thereof and permanently communicatingwith said upper end, said valve housing defining a passage vayconnecting said upper end of said column to said fluid motor means; saidvalve means further including a first valve element arranged adjacentthe upstream end of said passageway and having a relatively low openposition and a relatively elevated closed position; said valve meansfurther including a second valve element arranged adjacent thedownstream end of said passageway and having a relatively low seal-odposition and a relatively elevated venting position, said second valveelement defining a duct allowing air under pressure to iiow from saidupper end of said column to said fluid motor means when said secondvalve element is in said seal-off position thereof; a stem connectingsaid first valve element and said second valve element to jointly raiseand jointly lower said first valve element and said second valveelement; a spring biasing said stem in an upward direction, a verticalinsulating rod arranged inside said column adapted to be pulleddownwardly to move said stem downwardly and compress said spring, andmeans including lever means and cam means allowing said spring to expandupon upward movement of said rod.

10. 'In a high-voltage circuit breaker the combination a vertical hollowinsulating column normally filled with air under pressure;

`a pair of tanks supplied with air under pressure from said columnarranged to both sides of the top end of said column, each of said pairof tanks housing relatively movable contact means, a blast valve andfiuid motor means for operating said contact means and said blast valveand responsive to the admission of air under pressure and to dumping ofair under pressure;

valve means comprising a metallic casing structure arranged in coaxialrelation to said column between said pair of tanks `and supported bysaid top end of said column and communicating with said column, `saidcasing structure defining a passageway extending substantially in adirection longitudinally of said column and having an orifice connectedby pipe lines to said fluid motor means for selectively admitting airunder pressure to and dumping air under pressure from said fluid motormeans;

a Valve stem arranged within said casing structure in coaxial relationto said column and adapted to be moved selectively in a directionlongitudinally thereof to two limit positions;

spring means biasing said stem to one of said two limit positionsthereof;

a first valve eiement mounted on said stem and having a surface adaptedto be acted upon by the pressure of air under pressure within saidcasing structure and within said column when said stem is in one 0f saidtwo limit positions thereof;

a first valve seat adjacent the upstream end of said passageway adaptedto be cooperatively engaged by a portion of said surface of said firstvalve element to close said passageway when said stern is in the otherof said two limit positions thereof;

a second valve element mounted on said stem defining an apertureextending substantially in said direction longitudinally of said columnand forming a portion lof said passageway, said second valve elementhaving a surface adapted to be acted upon by the pressure of air underpressure within said casing structure and within said column when saidstem is in said other of said two limit positions thereof;

a second valve seat intermediate said upstream end of said passagewayand said orifice of said casing structure adapted to be cooperativelyengaged by a portion of the surface of said second valve elementsituated on the side thereof remote from said orifice;

and an insulating rod arranged inside said column adapted to be moved insaid direction longitudinally of said column to operate said sternpositively from the bottom of said column.

l1. A valve for the control of a iiow of gas under pressure comprising acasing structure having a longitudinal axis and deining a passagewayextending substantially along said longitudinal axis, said casingstructure further defining an orice allowing gas under pressurecontained within said casing structure to escape therefrom along saidlongitudinal axis;

a valve stem housed within and arranged along said longitudinal axis ofsaid casing structure and adapted to be moved selectively in a directionlongitudinally thereof to two limit positions;

spring means biasing said stem to one of said two limit positionsthereof;

a first valve element mounted on said stem and having a surface adaptedto be acted upon by the pressure of gas under pressure within saidcasing structure when said stem is in one of said two limit positionsthereof;

a first valve seat adjacent the upstream end of said passageway adaptedto be cooperatively engaged by a portion of said surface of said rstvalve element to close said passageway when said ste-m is in the otherof said two limit positions thereof;

a second valve element mounted on said stern defining an apertureextending substantially in the direction of said longitudinal axis ofsaid casing structure and forming a portion of said passageway;

and a second valve seat intermediate said upstream end of saidpassageway and said orifice of said casing structure adapted to becooperatively engaged by the side of said second valve element remotefrom said orifice.

References Cited in the file of this patent UNITED STATES PATENTSTrencham Apr. 4, 1939 Prince Nov. 12, 1940 Forwald Nov. 22, 1955Williams et al. Apr. 7, 1959 Hoge Oct. 201, 1959 Schulz Dec. 13, 1960Baker Dec. 20, 1960 FOREIGN PATENTS Great Britain Mar. 25, 19418

1. IN A HIGH-VOLTAGE CIRCUIT BREAKER THE COMBINATION OF A VERTICALHOLLOW INSULATING COLUMN; RELATIVELY MOVABLE CONTACT MEANS ARRANGEDADJACENT THE UPPER END OF COLUMN; A BLAST VALVE ARRANGED ADJACENT THEUPPER END OF SAID COLUMN FOR PRODUCING AN ARC-EXTINGUISHING BLAST ACROSSTHE GAP FORMED BETWEEN SAID CONTACT MEANS UPON SEPARATION THEREOF; MEANSFOR FILLING SAID COLUMN WITH AIR UNDER PRESSURE; A PNEUMATIC SYSTEM FORSAID CONTACT MEANS AND BLAST VALVE ARRANGED ADJACENT THE UPPER END OFSAID COLUMN AND INCLUDING FLUID MOTOR MEANS FOR OPERATING SAID CONTACTMEANS AND SAID BLAST VALVE; SAID PNEUMATIC SYSTEM FURTHER COMPRISINGVALVE MEANS FOR SELECTIVELY ADMITTING AIR UNDER PRESSURE TO SAID FLUIDMOTOR MEANS AND FOR VENTING SAID FLUID MOTOR MEANS TO ATMOSPHERE; SAIDVALVE MEANS INCLUDING A VALVE HOUSING ALIGNED WITH SAID COLUMN,SUPPORTED BY THE UPPER END THEREOF AND PERMANENTLY COMMUNICATING WITHSAID UPPER END, SAID VALVE HOUSING DEFINING A SUBSTANTIALLY STRAIGHTPASSAGEWAY IN COAXIAL RELATION TO SAID COLUMN; A FIRST VALVE ELEMENTARRANGED ADJACENT THE UPSTREAM END OF SAID PASSAGEWAY AND HAVING A FIRSTLIMIT POSITION CAUSING OPENING OF SAID PASSAGEWAY AND A SECOND LIMITPOSITION CAUSING CLOSING OF SAID PASSAGEWAY; A SECOND VALVE ELEMENTARRANGED IN COAXIAL RELATION TO SAID FIRST VALVE ELEMENT ADJACENT THEDOWNSTREAM END OF SAID PASSAGEWAY AND HAVING A FIRST LIMIT POSITIONCAUSING SAID PASSAGEWAY TO BE SEALED OFF FROM ATMOSPHERE AND A SECONDLIMIT POSITION CAUSING SAID PASSAGEWAY TO BE VENTED TO ATMOSPHERE; ACOMMON STEM SUPPORTING SAID FIRST VALVE ELEMENT AND SAID SECOND VALVEELEMENT TO MOVE SAID FIRST VALVE ELEMENT AND SAID SECOND VALVE ELEMENTJOINTLY TO SAID FIRST LIMIT POSITIONS AND SAID SECOND LIMIT POSITIONSTHEREOF; SPRING MEANS BIASING SAID FIRST VALVE ELEMENT AND SAID SECONDVALVE ELEMENT TO SAID SECOND LIMIT POSITIONS THEREOF; SAID SECOND VALVEELEMENT DEFINING A DUCT EXTENDING IN A DIRECTION SUBSTANTIALLYLONGITUDINALLY OF SAID STEM CAUSING THE PRESSURE OF AIR PASSING SAIDFIRST VALVE ELEMENT AND SAID DUCT TO MAINTAIN SAID SECOND VALVE ELEMENTAND SAID FIRST VALVE ELEMENT IN SAID SECOND LIMIT POSITIONS THEREOF; ANDAN INSULATING ROD ARRANGED INSIDE SAID COLUMN ADAPTED TO BE MOVED INDIRECTIONS LONGITUDINALLY THEREOF AND OPERATIVELY RELATED TO SAID STEMTO OPERATE SAID VALVE MEANS FROM THE BOTTOM END OF SAID COLUMN.